20Q.net is an online version of 20 Questions. Think of an object (animal, vegetable, mineral or other) and the site will try to guess what you’re thinking of in 20 questions or less. Some of the questions it asks are a bit silly, but generally it works quite well.
Another AI-based quiz is Guess The Dictator or Sit-Com Character. It usually guesses correctly but struggles on non-US TV characters.